Apparatus and method for ossicular fixation of implantable hearing aid actuator

Abstract

The invention is directed to a fixation apparatus and method for interfacing an implantable hearing aid actuator with the ossicular chain of a patient. The fixation apparatus may include one or more surface discontinuities to enhance tissue fixation and thereby yield enhanced mechanical coupling and vibratory response. Surface discontinuities may be in the form of surface pores, surface asperities and complex surface shapes such as grooves, slots, lips or openings formed in the fixation apparatus. The fixation apparatus may also and/or alternatively include a portion or component that is deflectable or that comprises a conditioned shape memory material that is activatable at bodily temperatures to yield a degree of lateral loading when the fixation apparatus is positioned within an opening defined within a bone of the ossicular chain of a patient, thereby yielding enhanced mechanical coupling.

What is claimed is:  
     
         1 . An implantable hearing aid actuator, comprising: 
 a transducer; and,    an apparatus, responsive to said transducer to communicate axial vibrations to an ossicular chain of a patient, wherein the apparatus includes at least one surface discontinuity integrally formed in the apparatus and located on the apparatus for inducing patient tissue attachment thereto.    
     
     
         2 . An implantable hearing aid actuator as recited in  claim 1 , wherein said at least one surface discontinuity comprises: 
 at least one of a complex surface shape, surface pores, and surface asperities.    
     
     
         3 . An implantable hearing aid actuator as recited in  claim 1 , wherein said at least one surface discontinuity comprises: 
 at least one slot extending across and rearwardly through a body portion from a distal end of said apparatus, wherein at least two leg members are defined.    
     
     
         4 . An implantable hearing aid actuator as recited in  claim 3 , wherein a first outer surface portion of each of said at least two leg members tapers outwardly from said distal end.  
     
     
         5 . An implantable hearing aid actuator as recited in  claim 3  wherein said at least two leg members are deflectable.  
     
     
         6 . An implantable hearing aid actuator as recited in  claim 4 , wherein a second outer surface portion of each of said at least two leg members tapers inwardly from the corresponding first outer surface portion.  
     
     
         7 . An implantable hearing aid actuator as recited in  claim 3 , wherein said at least one surface discontinuity comprises two transverse slots extending across and rearwardly away from said distal end, wherein four leg members are defined.  
     
     
         8 . An implantable hearing aid actuator as recited in  claim 3 , further comprising: 
 a selectively actuatable spring member positionable in said at least one slot, wherein said spring member comprises a shape memory material.    
     
     
         9 . An implantable hearing aid actuator as recited in  claim 3 , wherein said body portion includes: 
 a first outer surface portion that tapers outwardly from said distal end.    
     
     
         10 . An implantable hearing aid actuator as recited in  claim 3 , wherein said at least one surface discontinuity further comprises: 
 at least one pair of adjacent enlarged and reduced sections in said body portion, wherein a stepped-down lip is defined between said enlarged and reduced sections.    
     
     
         11 . An implantable hearing aid actuator as recited in  claim 1 , wherein said at least one surface discontinuity comprises: 
 at least one hole extending crosswise through a body portion of said apparatus.    
     
     
         12 . An implantable hearing aid actuator as recited in  claim 1 , wherein said at least one surface discontinuity comprises: 
 at least one pair of adjacent enlarged and reduced sections in a body portion of said apparatus, wherein a stepped-down lip is defined between said enlarged and reduced sections.    
     
     
         13 . An implantable hearing aid actuator as recited in  claim 12 , wherein at least a distal one of said enlarged sections is of a frusto-conical configuration.  
     
     
         14 . An implantable hearing aid actuator as recited in  claim 1 , wherein said at least one surface discontinuity includes: 
 a plurality of frusto-conical sections spaced along a body portion of said apparatus.    
     
     
         15 . An implantable hearing aid actuator as recited in  claim 1 , wherein said at least one surface discontinuity is defined by an outer surface having at least one of said surface pores and said surface asperities, and wherein said outer surface comprises a material selected from a group consisting of: a ceramic material, a plastic material, a composite ceramic material, and a composite plastic material.  
     
     
         16 . An implantable hearing aid actuator as recited in  claim 1 , wherein said apparatus includes: 
 a vibratory member connectable to and extendable away from said transducer.    
     
     
         17 . An implantable hearing aid actuator as recited in  claim 1 , wherein said apparatus includes: 
 a first apparatus to couple with said ossicular chain of the patient and including said at least one surface discontinuity; and    a second apparatus responsive to said transducer to communicate said axial vibrations to said first apparatus.    
     
     
         18 . An implantable hearing aid actuator, comprising: 
 a transducer;    a first apparatus to couple with an ossicular chain of a patient and including at least one surface discontinuity located and adapted for inducing patient tissue attachment between said ossicular chain and said first apparatus;    a second apparatus responsive to said transducer to communicate axial vibrations to said first apparatus, wherein said first and second apparatus are selectively connectable and disconnectable.    
     
     
         19 . An implantable hearing aid actuator as recited in  claim 18 , wherein said at least one surface discontinuity comprises: 
 at least one of a complex surface shape, surface pores and surface asperities.    
     
     
         20 . An implantable hearing aid actuator as recited in  claim 18 , wherein said at least one surface discontinuity comprises: 
 at least one slot extending across and rearwardly through a body portion from a distal end of said apparatus, wherein at least two leg members are defined.    
     
     
         21 . An implantable hearing aid actuator as recited in  claim 20 , wherein a first outer surface portion of each of said at least two leg members tapers outwardly from said distal end.  
     
     
         22 . An implantable hearing aid actuator as recited in  claim 20 , wherein said at least two leg members are deflectable.  
     
     
         23 . An implantable hearing aid actuator as recited in  claim 21 , wherein a second outer surface portion of each of said at least two leg members tapers inwardly from the corresponding first outer surface portion.  
     
     
         24 . An implantable hearing aid actuator as recited in  claim 20 , wherein said at least one surface discontinuity comprises two transverse slots extending across and rearwardly away from said distal end, wherein four leg members are defined.  
     
     
         25 . An implantable hearing aid actuator as recited in  claim 20 , further comprising: 
 a selectively actuatable spring member positionable in said at least one slot, wherein said spring member comprises a shape memory material.    
     
     
         26 . An implantable hearing aid actuator as recited in  claim 21 , wherein said body portion includes: 
 a first outer surface portion that tapers outwardly from said distal end.    
     
     
         27 . An implantable hearing aid actuator as recited in  claim 20 , wherein said at least one surface discontinuity further comprises: 
 at least one pair of adjacent enlarged and reduced sections in said body portion, wherein a stepped-down lip is defined between said enlarged and reduced sections.    
     
     
         28 . An implantable hearing aid actuator as recited in  claim 18 , wherein said at least one surface discontinuity comprises: 
 at least one hole extending crosswise through a body portion of said apparatus.    
     
     
         29 . An implantable hearing aid actuator as recited in  claim 18 , wherein said at least one surface discontinuity comprises: 
 at least one pair of adjacent enlarged and reduced sections in a body portion of said apparatus, wherein a stepped-down lip is defined between said enlarged and reduced sections.    
     
     
         30 . An implantable hearing aid actuator as recited in  claim 29 , wherein at least a distal one of said enlarged sections is of a frusto-conical configuration.  
     
     
         31 . An implantable hearing aid actuator as recited in  claim 18 , wherein said at least one surface discontinuity includes: 
 a plurality of frusto-conical sections spaced along a body portion of said apparatus.    
     
     
         32 . An implantable hearing aid actuator as recited in  claim 18 , wherein said at least one surface discontinuity is defined by an outer surface having at least one of said surface pores and said surface asperities, and wherein said outer surface comprises a material selected from a group consisting of: a ceramic material, a plastic material, a composite ceramic material, and a composite plastic material.  
     
     
         33 . An implantable hearing aid actuator as recited in  claim 32 , wherein said outer surface of said apparatus comprises a material selected from a group consisting of: hydroxyapatite and tricalcium phosphate.  
     
     
         34 . An implantable hearing aid actuator as recited in  claim 18 , wherein said apparatus includes: 
 a vibratory member connectable to and extendable away from said transducer.